A controlling valve, especially a ball valve, for a gaseous and liquid flow medium can comprise a housing, connector pipes, a flow-adjusting component and valve seat components. The flow-adjusting component and the valve seat components have suitable flow ducts, which are provided in sintered ceramic material. This sintered ceramic material, the so-called industrial ceramic, can take the physical and/or chemical action which various flow materials, especially corrosive flow materials, exert on it.
Generally the flow-adjusting component, which seals without using elastomeric materials, fits the valve seat components. An appropriate precision machining is required for this purpose. The housing and connector pipes are generally made of a metal, usually steel.
In the known controlling valve, on which the invention is based (e.g. German Patent No. 35 45 547) the flow-adjusting component and the associated valve seat components are solid and are made from sintered ceramic material. This arrangement is expensive because the advantageous properties of the sintered ceramic material are only needed in the vicinity of the flow ducts and are only necessary there. Nevertheless, up to now a solid flow-adjusting component made completely from sintered ceramic material has been required and deemed necessary.